Fracture surface of Ti-5%TiC
Enabling & Support

Metal Matrix Composites (MMCs) as high performance metallic material

03/02/2017 595 views 0 likes
ESA / Enabling & Support / Space Engineering & Technology / Shaping the Future
 Programme:  TRP Workplan  Achieved TRL:  2
 Reference:  T724-303QT  Closure:  2016
 Contractor(s):  AAC (AT), Tecnalia (ES), RHP (AT), RTBV (AT), TU Wien (AT)

 
Metal matrix composites (MMCs) have developed during the last decade and some of them could be used for structural applications – potentially boosting the performances by 50% or more compared with pristine metallic solutions. Developing MMCs is challenging as it requires excursions at high temperature where undesirable chemistry / stresses generation can be initiated.

Objectives
The main objective of the study was to investigate few materials showing, on paper, good performances. Mg-8%Li reinforced with carbon fibres, Ti6Al4V reinforced with TiB and Mg (AZ91) reinforced with alumina nano particles.

Complex demonstrator Ti-5%TiC with brazed joint
Complex demonstrator Ti-5%TiC with brazed joint

Achievements
In Mg-Li matrix composite, Li diffuses very quickly in the carbon fibres inducing swelling and Lithium carbide formation – more work would be needed to have reinforcement compatible with Li, this later providing very interesting properties to Mg when added in large enough quantity (8%). In Mg reinforced with nanoparticles, particle distribution remains unsatisfactory, the mixing proved challenging. As back up, micro-size particles were used and processing developed. In Ti6Al4V, TiB has been swapped for TiC with lower vol%. The composites passed the SCC test opening the door to structural applications.

Benefits
The Ti64V based composite is a candidate for high performance applications. Activity conducted with unofficial sub-contractor: Slovak academy of Science which worked on Mg-Li matrix composite - allowing this institute to understand the space industry requirements.

Related Links